The present invention relates generally to a carpenter's level, and more particularly, to an extensible carpenter's level. A carpenter's level may be used to determine the angular position of a given plane or surface relative to a reference plane or surface. A carpenter's level generally includes a level bubble mounted in a housing. The level bubble is mounted in the housing at a predetermined orientation relative to a reference edge of the housing. As a result, the angular position of a surface may be determined by placing the reference edge of the housing against the surface.
In order to achieve optimum accuracy, the length of the reference edge of the housing is preferably about equal to the length of the surface to be checked. If the reference edge is too short, the carpenter's level may be overly sensitive to undulations in the surface. On the other hand, the carpenter's level may be unnecessarily cumbersome if it is too long. Consequently, it is often necessary to have carpenter's levels of varying lengths for a particular job.
Extensible carpenter's levels have been advanced in an attempt to eliminate the need to carry several carpenter's levels of varying lengths. However, known extensible carpenter's levels are unnecessarily complicated and expensive to manufacture. Consequently, a need exists for a stable, extensible carpenter's level which is easy to use and manufacture.
The present invention provides an improved extensible carpenter's level which is slidably adjustable between a collapsed position and a fully-extended position. The reference edges of the level remain substantially aligned in the same plane regardless of the position of the level. A preferred embodiment of the level includes an innerslide, a first outerslide, and a second outerslide. The innerslide has a first set of tracks and a second set of tracks. The outerslides are slidably connected to the innerslide. The first outerslide and the second outerslide are preferably adapted to slide independently each other. The first outerslide is adapted to slide along the first set of tracks, and the second outerslide is adapted to slide along the second set of tracks. At least one of the slides includes at least one level bubble. Different types of level bubbles may be mounted in the same level to allow for a variety of measurements. For example, one level may include a horizontal level bubble, a vertical level bubble, and a level bubble that measures a predetermined angle, e.g., 30.degree..
The cross section of the innerslide may be generally I-shaped. The first set of tracks is preferably comprised of a first track on a top side of the innerslide and a second track on a bottom side of the innerslide. In addition, the second set of tracks is preferably comprised of a third track on the top side of the innerslide and a fourth track on the bottom side of the innerslide. However, it should be recognized that the level may have any appropriate number of tracks located in any appropriate positions on the innerslide.
The first outerslide is preferably comprised of a first extension member which is connected to a first end member. The first extension member may be longer than the first end member. The first extension member preferably has a first tongue which is adapted to slide in the first track and a second tongue which is adapted to slide in the second track. On the other hand, the first end member preferably has a third tongue which is adapted to slide in the third track and a fourth tongue which is adapted to slide in the fourth track. The second outerslide is preferably similar to, but opposing, the first outerslide. The second outerslide is preferably comprised of a second extension member which is connected to a second end member. The second extension member may be longer than the second end member. The second extension member preferably has a fifth tongue and a sixth tongue, wherein the fifth tongue is adapted to slide in the third track and the sixth tongue is adapted to slide in the fourth track. Furthermore, the second end member preferably has a seventh tongue which is adapted to slide in the first track and an eighth tongue which is adapted to slide in the second track. The first extension member preferably abuts the second end member and the second extension member preferably abuts the first end member when the carpenter's level is in the collapsed position.
The level may be magnetized. For example, any of the slides may be made from a magnetized material. For another example, one or more magnets may be secured to any of the slides. Preferably, a magnetic strip is adhered to a reference edge of the level. Magnetization preferably helps to hold the reference edge of the level securely against an appropriate surface, e.g., a metal surface, that is being measured. It also preferably helps to prevent the level from falling off a suitable surface during a measurement.
The carpenter's level preferably includes means for releasably locking the position of at least one of the outerslides relative to the innerslide at predetermined intervals. This feature preferably facilitates the use of the level at intermediate lengths between the collapsed position and the fully-extended position. The means may be a spring-loaded ball bearing or pin that is releasably engaged by grooves, cutouts, or notches that are spaced at predetermined intervals on the innerslide or either of the outerslides. It is preferred that a user can disengage the spring-loaded ball bearing or pin by sliding the outerslide relative to the innerslide.
Another embodiment of the level is similar to the embodiment described above except that the innerslide has tongues. In this embodiment, the innerslide has a first set of tongues and a second set of tongues. The first outerslide is slidably connected to the innerslide, and it is adapted to slide along the first set of tongues. The second outerslide is also slidably connected to the innerslide, and it is adapted to slide along the second set of tongues. At least one of the slides includes at least one level bubble.
The first set of tongues may be comprised of a first tongue on a top side of the innerslide and a second tongue on a bottom side of the innerslide. The second set of tongues may be comprised of a third tongue on the top side of the innerslide and a fourth tongue on the bottom side of the innerslide. In such an embodiment, the first outerslide preferably has a first extension member which is connected to a first end member, and the second outerslide preferably has a second extension member which is connected to a second end member. The first extension member has a first track which is adapted to slide along the first tongue and a second track which is adapted to slide along the second tongue. The first end member has a third track which is adapted to slide along the third tongue. The first end member also has a fourth track which is adapted to slide along the fourth tongue. On the other hand, the second extension member has a fifth track which is adapted to slide along the third tongue and a sixth track which is adapted to slide along the fourth tongue. Furthermore, the second end member has a seventh track which is adapted to slide along the first tongue and an eighth track which is adapted to slide along the second tongue.
This embodiment may also include the optional and preferred features of the first embodiment.
In addition to the novel features and advantages mentioned above, other objects and advantages of the present invention will be readily apparent from the following descriptions of the drawings and preferred embodiments.